As shown in FIG. 11, one prior art battery charger 101 has a generally box shaped, clam shell housing 103 with a cover 105 and a base 107. A printed circuit board 109 is mounted in the base and extends generally parallel to a bottom wall 111 of the base portion. The battery charging circuit (not shown) formed in and supported on the circuit board 109 contains a relatively large cylindrical, spirally wound, metallized film capacitor 113 electrically connected in the circuit by pair of lead wires 115 (only one shown) extending respectively from the opposed ends of the capacitor. The capacitor film 117 is spirally wound on an axial core 119. In finished form, the ends of the capacitor are formed by the flush edges of the film 117 and core 119. To provide an impact and shock resistant mounting, the capacitor 113 is potted in a rectangular box shaped support 121 which is sandwiched between the cover 105 and base 107 of the housing 103. One side 123 of the support 121 is open for insertion of the capacitor 113 and potting material 125. The capacitor support 121 has a plurality of spaced legs 127, 129 extending integrally from a bottom wall 131 of the support and resting on the bottom wall 111 of the base 107. One leg 127 (only one shown) is located at each axial end of support 121. Two legs 129 (only one shown) are located adjacent the rear wall 130 of support 121. The support 121 and capacitor 113 extend above and across the surface of the circuit board 109 with the legs 127, 129 straddling the perimeter of the board. A cushion 135 is disposed between the upper surface of the top wall 137 of the capacitor support and the lower surface of the top wall 139 of the cover to provide a cushioned stable mounting within the housing 103. The engagement of the legs 127, 129 with the outside edges of the circuit board also contribute to the axial and transverse stability of the capacitor support 121.
Prior art chargers manufactured as described above provide adequate impact and shock resistance. However, they have been found to suffer from a number of disadvantages in automated manufacture and part cost. One disadvantage is that it was difficult to design a fixture for supporting the capacitor relative to the circuit board to solder the capacitor in circuit at the same time as other small components in an automated wave solder machine. Prior to running the board through the wave solder machine, the electrical components are loosely mounted on the circuit board by inserting the leads through openings in the board. Then the board is placed on a solder machine fixture which is moved between stations for soldering, washing and electrical testing of the circuit. Because the capacitor is large and unwieldy, it was not practical to mount the capacitor on the board for automated soldering and full functional testing of the completed pc board circuit at the last machine station. For this reason, the capacitor was inserted on the board and soldered manually following processing of the board in the wave solder machine. Following completion of these manual assembly steps, then a full functional test of the completed pc board circuit could be conducted. Therefore, the prior art charger required manual labor steps which would be desirable to automate.
A second disadvantage of the prior art charger is that the capacitor support and potting add labor and part cost to the product. The support and potting serve the sole purpose of providing a shock and impact resistant mounting for the capacitor. Therefore, the prior art charger required additional labor and part cost which could be reduced if a simpler, mechanically stable support could be developed.